Multipoint-to-multipoint radio data transport

ABSTRACT

The invention concerns a system for multipoint-to-multipoint radio data transport, comprising a device for switching samples of digitised radio data called samples, transmitted by a device for the digital processing of antenna signals called antenna device (RU1, RU2), via a first data link (DL11, DL12), to a plurality of recipient antenna controller devices (DU1, DU2) identified by a respective plurality of controller identifiers, the switching device (DD) comprising the following modules: interception of first data frames (T11, T12) from the antenna device and intended for the plurality of controller devices, the first frames comprising the samples, demultiplexing the samples from the intercepted first data frames, extracting the controller identifiers from the intercepted first data frames, grouping together the demultiplexed samples by controller identifier, multiplexing the samples by group in second data frames (T21, T22), a second data frame being associated with a controller identifier, transmitting the second data frames via a plurality of second data links (DL21, DL22) associated respectively with the plurality of recipient antenna controller devices.

FIELD OF THE INVENTION

The application for invention lies in the field of mobile accessnetworks, and more particularly in the field of the collection anddistribution of radio data between the radio units in proximity to theantennas and the antenna controller equipment items.

PRIOR ART

In a traditional mobile access network architecture, a base station isinstalled for example on a mast or a building and comprises a radio unit(RU) for each antenna, and a control unit (or digital unit, DU) for eachradio unit, in proximity to the antenna, for example at the base of themast or in a technical room of the building.

The radio unit of a base station is, among other things, responsible forthe reception and transmission of the radio signal from and to theantenna, and for its digitization for transmission to the control unit.

The radio units are also called radiofrequency heads, or remote radioheads (RRH) or radio equipment (RE). For clarity and simplicity, theyare hereinafter called antenna devices, it being understood that thisdesignation covers the device allowing the antenna to be connected to acontrol unit.

The control unit of a base station is, among other things, responsiblefor the processing of the data contained in the digital signal processedby the radio unit and for guaranteeing the connection to atelecommunication network.

The control units are also called baseband unit (BBU) or remoteequipment control (REC). For clarity and simplicity, they arehereinafter called antenna controller devices, or more simply antennacontrollers, it being understood that this designation covers the deviceallowing the control unit to be connected to an antenna device.

The connection between the antenna device and the antenna controller ismade by a digitized radio data link borne by an optical fiber or awireless radio link and using the CPRI (Common Public Radio Interface),OBSAI (Open Base Station Architecture Initiative) or ORI (Open RadioEquipment Interface; ORI being based on CPRI) protocol. This link ishereinafter called CPRI link because the CPRI protocol is the mostwidely used, it being understood that this designation covers the otherprotocols also.

With the proliferation of mobile access networks and the attendantchanges to the standards, the mobile communications operators have atendency to distance the controllers from the antenna sites andtherefore from the antenna devices, depending on criteria which arespecific to them. For example, one operator may group together in asingle plant, away from the antennas, some of its antenna controllersserving the antennas of several antenna sites. Furthermore, since theantennas and the antenna devices can be shared between a number ofoperators, the need emerges to connect an antenna device to severalcontrollers, one controller per operator, in premises that may or maynot be distinct, by as many distinct CPRI links. The “CPRI specificationv5.0” standard stipulates, in section 2.3, that an antenna device can beserved by a plurality of antenna controller devices, by relying onpoint-to-point CPRI links between the antenna device and each of theantenna controller devices.

This multiplicity of CPRI links relying on as many optical fibers orwireless radio links represents a cost, combined with the increasingdistance between controllers and antennas, imposes constraints on theorganization of the sites hosting the antenna controllers, which are allthe more of a nuisance when the controllers are managed by differentoperators.

One of the aims of the invention is to remedy these drawbacks in theprior art.

SUMMARY OF THE INVENTION

The invention improves the situation using a device for switchingdigitized radio data samples called samples, transmitted by a digitalantenna signal processing device called antenna device, through a firstdata link, to a plurality of recipient antenna controller devicesidentified by a respective plurality of controller identifiers, theswitching device comprising the following modules:

-   -   interception of first data frames from the antenna device and        intended for the plurality of controller devices, the first        frames comprising the samples,    -   demultiplexing of the samples of the intercepted first data        frames,    -   extraction of the controller identifiers from the intercepted        first data frames,    -   grouping together of the demultiplexed samples by controller        identifier,    -   multiplexing of the samples by group in second data frames, a        second data frame being associated with a controller identifier,    -   transmission of the second data frames via a plurality of second        data links associated respectively with the plurality of        recipient antenna controller devices.

The switching device according to the invention resolves the problems ofthe prior art linked to the multiplicity of links between an antennadevice and the controller devices, and the increasing distance betweenthem, by remotely siting the point where the data frames have to beswitched to the correct recipient controller device. In effect, byvirtue of the invention, the data frames transmitted by the antennadevice are intercepted by the switching device which is responsible fortransmitting them to the correct recipient controller device.

In this way, the location of the controller devices is no longerconstrained by that of the antenna device. It is sufficient to locatethe switching device according to the location of the controllerdevices.

The invention relates also to a digital antenna signal processingdevice, called antenna device, transmitting digitized radio datasamples, called samples, to a plurality of recipient antenna controllerdevices identified by a respective plurality of controller identifiers,the antenna device comprising the following modules:

-   -   obtaining of the samples,    -   identification of their respective controller device,    -   multiplexing of the samples in first digitized radio data        frames, called first data frames,    -   insertion in the first data frames of the recipient controller        identifiers, corresponding to the multiplexed samples,    -   transmission of the first frames to the plurality of antenna        controller devices via a first data link to the plurality of        recipient antenna controller devices.

In the CPRI standard, the digitized data samples are called “AxC”(Antenna-Carrier) and represent a quantity of data in digitized form, astransported in analog form by one and the same carrier between anantenna and a mobile terminal, that is to say transported in thefrequency band or bands allocated to the mobile terminal operator. Eachsample therefore corresponds to a data block intended to be transportedin a radio link between an antenna and a mobile terminal, within afrequency band specifically assigned to a mobile operator.

It will be recalled that the invention relates to the part betweenantenna and network, and not between antenna and mobile terminals. In amulti-operator environment, according to the prior art described in theCPRI standard, before transmitting data frames, an antenna device has tosort the samples in order to not mix them between several operators(between several carriers), because the antenna controller device ofeach operator, which is the recipient of these frames and is linked by adistinct CPRI link to the antenna device, does not perform this sortitself.

According to the invention, the antenna device does not sort the AxCsamples and does not transmit them over dedicated links to severalcontroller devices, but multiplexes them in order for them to be mixedin data frames which can thus be transmitted over a single link, thusavoiding the need to use a plurality of separate links.

These frames, called “CPRI frames” in the standard, are of the sameformat as those which are exchanged between an antenna device and acontroller device according to the prior art, which minimizes themodifications needed in the devices at each end of the link.

The invention relates also to a transmission system for digitized radiodata samples called samples, between at least one digital antennaprocessing device, called antenna device, and a plurality of recipientantenna controller devices identified respectively by a controlleridentifier, the system comprising at least one antenna device such asthat which has just been described, and one switching device such asthat which has just been described.

In the transmission system according to the invention, the antennadevice is connected to a switching device which is itself connected tothe different dedicated antenna controller devices for each operator.

The link between the antenna device and this switching device, and theframes that it transports, that is to say CPRI frames, are of the samekind as the direct links with the antenna controller devices accordingto the prior art.

Likewise, the links between the switching device and each of the antennacontroller devices, as well as the frames that they transport, that isto say CPRI frames, are of the same kind as the direct links with theantenna controller devices according to the prior art.

No modification is therefore needed in the antenna controller devices,which can continue to operate as if they had a direct point-to-pointlink with the antenna device.

By virtue of the first link between the antenna device and the switchingdevice, it is therefore easy to remotely site to a great distance thesplitting point to the different antenna controller devices, andtherefore to choose for the latter a location distant from the antennas,without any modification being necessary at their level.

Furthermore, such a transmission system according to the inventionfurther makes it possible to connect more than one antenna device to theplurality of antenna controllers, still without any modification beingnecessary at their level, in the case where one or more of the antennacontrollers are able to control a number of antennas at the same time,as is also provided for in the “CPRI specification v5.0” standard. Inother words, the system according to the invention also allows for thecreation and use of a multipoint-to-multipoint network between antennadevices and antenna controllers.

According to one aspect of the invention, the transmission systemfurther comprises first and second transport modules, the firsttransport module being arranged to:

-   -   receive the first data frames through at least one first data        link,    -   encapsulate the first data frames in transport frames,    -   transmit the transport frames to the second transport module        through a transport link,        and the second transport module being arranged to:    -   receive the transport frames through the transport link,    -   obtain the first data frames by de-encapsulation from the        transport frames,    -   deliver the de-encapsulated first data frames to the switching        device.

By virtue of this aspect, the constraints of location of the antennacontroller devices, specific to the CPRI links, disappear completely. Ineffect, by encapsulating the CPRI frames in frames of higher level, theCPRI frames can take a path in an existing transport network, such as anEthernet network or a G.709 optical data network, for example a pathbetween a first transport equipment item close to the antenna device anda second transport equipment item comprising the switching device. Forthat, it is sufficient for the first data link to be set up between theantenna device and a transport device which is a point of entry to thistransport network, and for the switching device to be adjacent toanother transport device which is a point of exit from this transportnetwork.

Thus, a greater flexibility is allowed in choosing the appropriatelocations for the antenna controller devices, even very far from theantennas. This advantage is obtained both for a point-to-multipointsystem, that is to say one antenna device to a plurality of controldevices, and for a multipoint-to-multipoint system, that is to say aplurality of antenna devices to a plurality of control devices.

The invention relates also to a communication equipment item, comprisingan interface with a transport network, a switching device such as thatwhich has just been described and a transport module arranged to

-   -   receive transport frames through the interface,    -   obtain data frames by de-encapsulation from the transport        frames,    -   deliver the de-encapsulated data frames to the switching device.

The invention relates also to a method for switching digitized radiodata samples called samples, transmitted by a digital antenna signalprocessing device called antenna device, to a plurality of recipientantenna controller devices identified by a respective plurality ofcontroller identifiers, the switching method comprising the followingsteps:

-   -   interception of first data frames from the antenna device and        intended for the plurality of controller devices, the first        frames comprising the samples,    -   demultiplexing of the samples of the intercepted first data        frames,    -   extraction of the controller identifiers from the intercepted        first data frames,    -   grouping together of the demultiplexed samples by controller        identifier,    -   multiplexing of the samples by group in second data frames, a        second data frame being associated with a controller identifier,    -   transmission of the second data frames via a plurality of second        data links associated respectively with the plurality of        recipient antenna controller devices.

The switching device is capable of implementing the switching methodwhich has just been described, in all its embodiments.

The invention relates also to a digital antenna signal processingmethod, for the transmission of digitized radio data samples, calledsamples, to a plurality of recipient antenna controller devicesidentified by a respective plurality of controller identifiers, thedigital antenna signal processing method comprising the following steps:

-   -   obtaining of the samples,    -   identification of their respective controller device,    -   multiplexing of the samples in first digitized radio data        frames, called first data frames,    -   insertion in the first data frames of the recipient controller        identifiers corresponding to the multiplexed samples,    -   transmission of the first frames to the plurality of antenna        controller devices via a first data link to the plurality of        recipient antenna controller devices.

According to one aspect of the invention, the identification step of thedigital antenna signal processing method comprises the following stepsfor each of the samples of a given first data frame:

-   -   identification of a frequency band associated with each sample;    -   obtaining of a controller identifier corresponding to the        identified frequency band.

By virtue of this aspect, it is possible to find the antenna controllerdevice to which each sample has to be handed over.

According to one aspect of the invention, the insertion step of thedigital antenna signal processing method comprises the following stepfor each of the first data frames:

-   -   insertion of the recipient controller identifiers corresponding        to the multiplexed samples in a field of the first data frames        called Vendor Specific in the CPRI standard.

By virtue of this aspect, it is possible to use an existing field in theCPRI standard, and no modification to the CPRI frame is necessary.

The digital antenna signal processing device is capable of implementingthe digital antenna signal processing method which has just beendescribed, in all its embodiments.

The various aspects of the invention which have just been described canbe implemented independently of one another or in combination with oneanother.

The invention relates also to a computer program comprising instructionsfor the implementation of the steps of the switching method which hasjust been described, when this program is executed by a processor.

The invention further relates to a storage medium that can be read by aswitching device, on which is stored the program which has just beendescribed, that can use any programming language, and be in the form ofsource code, object code, or intermediate code between source code andobject code, such as in a partially compiled form, or in any otherdesirable form.

The invention relates also to a computer program comprising instructionsfor the implementation of the steps of the digital antenna signalprocessing method which has just been described, when this program isexecuted by a processor.

The invention relates finally to a storage medium that can be read by adigital antenna signal processing device, on which is stored the programwhich has just been described, that can use any programming language,and be in the form of source code, object code, or intermediate codebetween source code and object code, such as in a partially compiledform, or in any other desirable form.

DESCRIPTION OF THE FIGURES

Other advantages and features of the invention will become more clearlyapparent on reading the following description of a particular embodimentof the invention, given as a simple illustrative and nonlimitingexample, and the attached drawings, in which:

FIG. 1 schematically presents a system for transmitting digitized radiodata samples, according to a first embodiment of the invention,

FIG. 2 schematically presents a system for transmitting digitized radiodata samples, according to a second embodiment of the invention,

FIG. 3 schematically presents a system for transmitting digitized radiodata samples, according to a third embodiment of the invention,

FIG. 4 presents an exemplary implementation of the digital antennasignal processing method according to one aspect of the invention,

FIG. 5 presents an exemplary implementation of the method for switchingdigitized radio data samples, according to one aspect of the invention,

FIG. 6 presents an exemplary structure of a digital antenna signalprocessing device, according to one aspect of the invention,

FIG. 7 presents an exemplary structure of a device for switchingdigitized radio data samples, according to one aspect of the invention.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

Hereinafter in the description, examples of a number of embodiments ofthe invention will be presented based on a transmission systemarchitecture for a base station conforming to the CPRI standard, but theinvention applies equally to other transmission system architectures,such as, for example, those using the OBSAI or ORI protocols.

FIG. 1 schematically presents a system for transmitting digitized radiodata samples, according to a first embodiment of the invention.

Using a digital antenna signal processing method which will be describedhereinbelow, the antenna device RU1 transmits data frames received by aradio antenna shared between a number of mobile network operators, tothe respective control devices of these operators.

In this example, the antenna is shared, and therefore the antenna deviceRU1 also, between two operators Op1 and Op2, the operators each havingtheir respective control device DU1 and DU2.

In this first embodiment, the antenna device RU1 is connected by a datalink DL11 to a switching device DD, which is itself connected to acontrol device DU1 by a link DL21 and to a device DU2 by a link DL22.

Data frames T11 are transmitted by the antenna device RU1 over the linkDL11. Each of these frames can comprise samples of data intended for thetwo control devices DU1 and DU2. These frames are received by theswitching device DD, which, after processing by a switching method whichwill be described hereinbelow, transmits data frames T21 to the controldevice DU1 and data frames T22 to the control device DU2. The dataframes T21 comprise only samples of data intended for the control deviceDU1, and the data frames T22 comprise only samples of data intended forthe control device DU2.

By virtue of the first data link DL11, the control devices DU1 and DU2can easily be distanced from the antenna device RU1. By virtue of therespective second data links DL21 and DL22, they further operate as ifthey were each connected by a dedicated data link to a dedicatedantenna, that is to say, a non-shared antenna.

FIG. 2 schematically presents a system for transmitting digitized radiodata samples, according to a second embodiment of the invention.

In this second embodiment, a transport link TL is inserted between thefirst data link DL11 and the second data links DL21 and DL22, by virtueof two transport modules TM1 and TM2 each comprised respectively in anentry point equipment item TE1 and an exit point equipment item TE2 ofone and the same transport network.

At the entry to the transport network, the transport module TM1encapsulates the data frames T11 transmitted by the antenna device RU1in transport frames TT, according to a format dependent on the type oftransport protocol used, for example Ethernet or G.709 ODN.

At the exit from the transport network, the transport module TM2receives the frames TT and de-encapsulates them in order to hand overthe data frames T11 to the switching device DD.

Advantageously, the location of the switching device can thus be chosenwith more flexibility, and the distance can be increased relative to theantenna device, while using an existing transport network.

FIG. 3 schematically presents a system for transmitting digitized radiodata samples, according to a third embodiment of the invention.

This third embodiment differs from the second in that each of theoperator control devices can control a number of shared antennas.

In this example, two antennas are shared, and therefore the antennadevices RU1 and RU2 also, between two operators Op1 and Op2, theoperators each having their respective control device DU1 and DU2.

The antenna device RU2 is connected by a data link DL12 to the transportmodule TM1.

At the entry to the transport network, the transport module TM1encapsulates, in transport frames TT, the data frames T11 and T12transmitted respectively by the antenna devices RU1 and RU2 through thedata links DL11 and DL12 without distinguishing the frames T11 and T12from one another.

At the exit from the transport network, the transport module TM2receives the frames TT and de-encapsulates them in order to hand overthe data frames T11 and T12 to the switching device DD.

By virtue of the combination of the links DL11, DL12, DL21, DL22, withthe switching device DD, each control device DU1 or DU2 operates as ifit controlled two antennas which were exclusively dedicated to it.

By virtue of the transport link TL, great flexibility is allowed in thelocating of the antenna devices and of the control devices relative toone another.

FIG. 4 presents an exemplary implementation of the digital antennasignal processing method, according to one aspect of the invention.Referring to FIGS. 1, 2 and 3, this method is implemented by an antennadevice such as the devices RU1 and RU2.

In a step E101, the antenna device RU1 obtains samples of data formattedin the form of AxC samples according to the CPRI standard.

In a step E102, the antenna device RU1 obtains, for each of thesesamples, an identifier which will subsequently enable it to address thedata contained in the samples to the correct destination. Thisidentifier can be associated with a range of radio frequencies used bythe antenna for a specific operator, Op1 or Op2, or be associateddirectly with one of these operators. In the first case, the step E102comprises a substep E103 of identification of the range of radiofrequencies used for the data sample, and a substep E104 of obtaining ofthe identifier of the operator to which this range of radio frequencieshas been assigned. Alternatively, the identifier can be the MAC addressor the IP address of the antenna controller device to which the datahave to be addressed, and/or a logical port of this device, it beingunderstood that the antenna controller device corresponds uniquely to asingle operator. It will be understood that whatever the identifierused, it must have the characteristic of being able to uniquely identifythe recipient antenna controller device of a data sample, that is to sayDU1 or DU2.

In a step E105, the antenna device RU1 multiplexes the samples in firstdata frames T11, in any order, which can be that in which they areobtained.

In a step E106, the antenna device RU1 inserts into each of the framesT11 the identifiers obtained in the step E102, so that it is possible toassociate the correct identifier with each sample contained in theframe. In the general case where the data frame T11 is a frame of CPRItype, the step E106 can to this end comprise a substep E107 of insertionof the identifiers in a field of the frame reserved for this purpose, oravailable. Such a field can be the “Vendor Specific” field. In order toavoid the unnecessary repetition of identical identifiers correspondingto consecutive samples, this field can comprise pointers at the placeswhere the AxC change identifier in the frame.

In a step E108, the antenna device RU1 transmits over a single link DL11the data frames T11, to a switching device DD, to which the recipientantenna controller devices DU1 and DU2 are connected.

In the third embodiment described with reference to FIG. 3, the antennadevice RU2 implements this method by performing the same steps, themethod ending with the transmission of frames T12 over the link DL12, tothe same switching device DD.

FIG. 5 presents an exemplary implementation of the method for switchingdigitized radio data samples, according to one aspect of the invention.Referring to FIGS. 1, 2 and 3, this method is implemented by a switchingdevice such as the device DD.

In a step E201, the switching device DD intercepts data frames T11 (andT12 in the case of the third embodiment of the invention). These framescan be obtained either directly from one or more antenna devices such asRU1 or RU2, or from a transport module such as TM2, referring to FIG. 1,2 or 3.

In a step E202, the switching device DD demultiplexes the data samplesof the intercepted data frames.

In a step E203, the switching device DD extracts from the intercepteddata frames controller identifiers corresponding to each of thedemultiplexed samples.

In a step E204, the switching device DD groups the demultiplexed samplesby controller identifier.

In a step E205, the switching device DD remultiplexes the samples bygroup in new data frames, a new data frame being associated with asingle controller identifier. There is therefore no longer a need toinsert any controller identifier in a new data frame.

In a step E206, the switching device DD transmits the new data framesvia data links DL21 and DL22 respectively to the recipient controllerdevices DU1 and DU2, by switching them over the correct link as afunction of the group of samples from which each new frame isremultiplexed.

The different embodiments of the invention which have just beendescribed can be combined together.

FIG. 6 presents an exemplary structure of a digital antenna signalprocessing device, according to one aspect of the invention.

The digital antenna signal processing device 100 implements the digitalantenna signal processing method, of which different embodiments havejust been described.

Such a device 100 can be implemented in a base station equipment item,such as a remote radio head.

For example, the device 100 comprises a processing unit 130, equippedfor example with a microprocessor μP, and driven by a computer program110, stored in a memory 120 and implementing the digital antenna signalprocessing method according to the invention. On initialization, thecode instructions of the computer program 110 are for example loadedinto a RAM memory, before being executed by the processor of theprocessing unit 130.

Such a device 100 comprises:

-   -   an obtaining module 140, capable of obtaining, from a radio        signal digitization module included in the antenna device,        digitized radio data samples (axc) associated with a frequency        band,    -   an identification module 150, capable of obtaining a control        device or operator identifier from a sample of digitized radio        data,    -   a multiplexing module 160, capable of multiplexing the samples        in a data frame,    -   an insertion module 170, capable of inserting the identifiers        corresponding to the samples of the frame in a data frame,    -   a transmission module 180, capable of transmitting the data        frames (cpri) to a switching device.

FIG. 7 presents an exemplary structure of a switching device fordigitized radio data samples, according to one aspect of the invention.

The switching device 200 implements the switching method, of whichdifferent embodiments have just been described.

Such a device 200 can be implemented in a transport equipment item, suchas an Ethernet router, or in an optical switch of ODN type.

For example, the device 200 comprises a processing unit 230, equippedfor example with a microprocessor μP, and driven by a computer program210, stored in a memory 220 and implementing the switching methodaccording to the invention. On initialization, the code instructions ofthe computer program 210 are for example loaded into a RAM memory,before being executed by the processor of the processing unit 230.

Such a device 200 comprises:

-   -   an interception module 240, capable of intercepting, from the        digital antenna signal processing device or a transport device,        data frames (cpri),    -   a demultiplexing module 250, capable of demultiplexing samples        of a data frame,    -   an extraction module 260, capable of extracting from a data        frame identifiers corresponding to the samples of the frame,    -   a grouping module 270, capable of grouping together the        demultiplexed samples by identifier,    -   a multiplexing module 280, capable of multiplexing the samples        by group in a data frame,    -   a transmission module 290, capable of transmitting the data        frames (cpri) to a plurality of antenna controller devices.

The modules described in relation to FIGS. 6 and 7 can be hardware orsoftware modules.

The exemplary embodiments of the invention which have just beenpresented are only a few of the embodiments that can be envisaged. Theyshow that the invention makes it possible to connect a plurality ofantennas shared between a number of operators to a plurality of antennacontroller devices, each antenna controller device being associated witha single operator, while using an existing protocol, by benefiting fromgreat flexibility in the choices of location and distancing of thecontroller devices relative to the antennas, and without requiring anymodification of the latter devices.

These examples show how the invention can be produced in the uplinkdirection, that is to say from the antenna device or devices to thecontroller devices.

In the downlink direction when there is only a single antenna device, itis sufficient for the switching device to also comprise a module forreceiving the data frames from each of the data links associated withthe controller devices, and a module for transmitting these framesunmodified to the data link associated with the antenna device.

When there are a number of antenna devices, a downlink switching device,similar to the uplink switching device which has just been described,can also be used. It differs therefrom simply by the extraction module,which extracts identifiers associated with the antenna devices, and notidentifiers associated with the controller devices.

This downlink switching device can be included in the equipment item TE1referring to FIG. 3, in the case where a transport link is used toincrease the range of the transmission system according to theinvention. It can also be included in the same communication equipmentitem as that comprising the uplink switching device.

The invention claimed is:
 1. A digital antenna signal processing device, called antenna device, transmitting in common public radio interface (CPRI) frames digitized radio data samples, called samples, to a plurality of recipient antenna controller devices identified by a respective plurality of controller identifiers, wherein the antenna device comprises a microprocessor configured for implementing the following modules: obtaining of the samples, identification of their respective controller device, multiplexing of the samples in first CPRI frames, insertion in the first CPRI frames of the recipient controller identifiers corresponding to the multiplexed samples, wherein the insertion comprises the following for each of the first CPRI frames: insertion of the recipient controller identifiers corresponding to the multiplexed samples in a field of the first CPRI frames called Vendor Specific, transmission of the first CPRI frames to the plurality of antenna controller devices via a first data link to the plurality of recipient antenna controller devices.
 2. A transmission system for digitized radio data samples called samples, between at least one digital antenna processing device, called antenna device, and a plurality of recipient antenna controller devices identified respectively by a controller identifier, wherein the system comprises at least one antenna device transmitting in common public radio interface (CPRI) frames digitized radio data samples, called samples, to a plurality of recipient antenna controller devices identified by a respective plurality of controller identifiers, wherein the antenna device comprises the following modules: obtaining of the samples, identification of their respective controller device, multiplexing of the samples in first CPRI frames, insertion in the first CPRI frames of the recipient controller identifiers corresponding to the multiplexed samples, wherein the insertion comprises the following for each of the first CPRI frames: insertion of the recipient controller identifiers corresponding to the multiplexed samples in a field of the first CPRI frames called Vendor Specific, transmission of the first CPRI frames to the plurality of antenna controller devices via a first data link to the plurality of recipient antenna controller devices; and one switching device for switching digitized radio data samples, transmitted in CPRI frames by a digital antenna signal processing device called antenna device, through a first data link, to a plurality of recipient antenna controller devices identified by a respective plurality of controller identifiers, wherein the switching device comprises the following modules: interception of first CPRI frames from the antenna device and intended for the plurality of controller devices, the first CPRI frames comprising the samples, demultiplexing of the samples of the intercepted first CPRI frames, extraction of the controller identifiers inserted by the antenna device, from the intercepted first CPRI frames, grouping together of the demultiplexed samples by controller identifier, multiplexing of the samples by group in second CPRI frames, a second CPRI frame being associated with a controller identifier, transmission of the second CPRI frames via a plurality of second data links associated respectively with the plurality of recipient antenna controller devices.
 3. The transmission system as claimed in claim 2, comprising first and second transport modules, the first transport module being arranged to: receive the first CPRI frames through at least one first data link, encapsulate the first CPRI frames in transport frames, transmit the transport frames to the second transport module through a transport link, and the second transport module being arranged to: receive the transport frames through the transport link, obtain the first CPRI frames by de-encapsulation from the transport frames, deliver the de-encapsulated first CPRI frames to the switching device.
 4. A digital antenna signal processing method, for the transmission in common public radio interface (CPRI) frames of digitized radio data samples, called samples, to a plurality of recipient antenna controller devices identified by a respective plurality of controller identifiers, wherein the digital antenna signal processing method comprises the following steps: obtaining of the samples, identification of their respective controller device, multiplexing of the samples in first in common public radio interface (CPRI) frames, insertion in the first CPRI frames of the recipient controller identifiers corresponding to the multiplexed samples, wherein the insertion comprises the following for each of the first CPRI frames: insertion of the recipient controller identifiers corresponding to the multiplexed samples in a field of the first CPRI frames called Vendor Specific, transmission of the first CPRI frames to the plurality of antenna controller devices via a first data link to the plurality of recipient antenna controller devices.
 5. The digital antenna signal processing method as claimed in claim 4, wherein the identification step comprises the following steps for each of the samples of a given first CPRI frame: identification of a frequency band associated with each sample; obtaining of a controller identifier corresponding to the identified frequency band.
 6. A computer program, stored on a non-transitory computer readable medium, the computer program comprising instructions for implementation of steps of a digital antenna signal processing method, when this digital antenna signal processing method is executed by a processor, the digital antenna signal processing method for the transmission in common public radio interface (CPRI) frames of digitized radio data samples, called samples, to a plurality of recipient antenna controller devices identified by a respective plurality of controller identifiers, wherein the digital antenna signal processing method comprises the following steps: obtaining of the samples, identification of their respective controller device, multiplexing of the samples in first in common public radio interface (CPRI) frames, insertion in the first CPRI frames of the recipient controller identifiers corresponding to the multiplexed samples, wherein the insertion comprises the following for each of the first CPRI frames: insertion of the recipient controller identifiers corresponding to the multiplexed samples in a field of the first CPRI frames called Vendor Specific, transmission of the first CPRI frames to the plurality of antenna controller devices via a first data link to the plurality of recipient antenna controller devices. 